If I were to bring a kegerator on board, I'd be more inclined to use 5 gal Corny kegs, instead of a half keg.

Back in the day, when I threw multi-kegger sized parties, kegs were cheaper than canned beer. However, back in the early 90s, canned beer dropped to about the same price, ounce for ounce, with the added convenience of not going flat if refrigeration or the CO2 was no longer available.

That's all in addition to what Geekatlrg posted about the heavy power draw, which is a very major concern. I'd have to have a LOT of fridge space available before I devoted that much of it to a 1/2 keg.

takes a lot of heavy refrigeration to keep a keg cold. That is a lot of weight and power. consistent refrigeration is key to keeping the foam down.

I worked a dive charter on a 60' mono with a full sized kegerator and a soda gun system. No issues with foam, even on rough passages. We would pre-chill the keg in a trashcan full of ice before putting it in, then the refrigeration was just needed to maintain temp.

We just turned the port patio seat/locker on a Seawind 1160 Cat in to a refrigerated box for the owners home brew keg. I've visited his boat now several times to check up on the system and make sure its all working right...